Converter Extension Reference#

Isaac ROS Deploy exposes four C++ extension interfaces for converting between LEAPP tensors and ROS 2 transports. Use this page to look up the interface contract. Follow How to add custom converters for the implementation workflow.

Topic Input Converters#

Topic input converters belong to isaac_ros_deploy_converters and derive from MessageToTensorConverter.

Member	Contract
`get_kind()`	Return the LEAPP semantic kind produced by the converter.
`get_message_type()`	Return the fully qualified ROS message type consumed by the converter.
`convert()`	Convert one serialized ROS message and return a tensor in message order.
`get_tensor_spec()`	Optionally return element names in message order. The runtime uses them to reorder elements into bundle order.

Register factories in initialize_input_converters(). A factory receives the input source name. The first message type registered for a kind is its default.

Source: message_to_tensor_converter.hpp

Topic Output Converters#

Topic output converters belong to isaac_ros_deploy_converters. Derive from TypedOutputConverter<MsgT> to reuse message allocation and serialization.

Member	Contract
`get_kind()`	Return the LEAPP semantic kind consumed by the converter.
`get_message_type()`	Return the fully qualified ROS message type produced by the converter.
`write()`	Write tensor values and shared metadata into the typed message.

Register factories in initialize_output_converters(). A factory receives the bundle-declared tensor shape and may return nullptr when it does not support that rank.

Source: tensor_to_message_converter.hpp

ROS 2 Control State Interface Converters#

State interface converters belong to isaac_ros_deploy_ros2_control and derive from StateInterfaceConverter.

Member	Contract
`get_required_state_interfaces()`	Return the hardware state-interface names to claim for the bundle’s element names.
`get_tensor_spec()`	Return element names in hardware order so the runtime can reorder them.
`read()`	Optionally override the default scalar reader. The default writes one claimed interface value to each element of a pre-allocated `[1, N]` tensor.

Register factories in initialize_state_interface_converters().

Source: state_interface_converter.hpp

ROS 2 Control Command Interface Converters#

Command interface converters belong to isaac_ros_deploy_ros2_control and derive from CommandInterfaceConverter.

Member	Contract
`get_required_command_interfaces()`	Return the hardware command-interface names to claim for the bundle’s element names, prefix, and suffix.
`get_tensor_spec()`	Return element names in hardware order so the runtime can reorder them.
`write()`	Optionally override the default scalar writer. The default flattens the tensor and writes one value to each claimed command interface.

Register factories in initialize_command_interface_converters().

Source: command_interface_converter.hpp